Shell Rotella Synth for Audi 1.8T

[thunderchild]

All, I am going to change my Audi's oil to Shell Rotella Synth 5w-40. I have read a little about it, and it would seem to be very good for my engine (1.8T). These engines are known to create some carbon. Oh, I drive an Audi TT 225QR. Any ideas good or bad about this oil?

 

[TooSlick]

I personally would not run a Group III based synthetic in any turbocharged gas engine application; even an Amsoil product. The reason is that petroleum derived basestocks (GP II and III), don't thermally decompose as cleanly as PAO's and/or esters and tend to leave more turbo deposits. Note that only Mobil 1 (of the off the shelf synthetics) was able to easily meet the new Honda oil spec for their turbo motor.

I have the same car and I'd probably run the Mobil 1, 10w-30 or the GC/0w-30 if I was looking for something off the shelf.

TS

 

[Reg# 43897]

I run GC in mine but have used RTS in the past - was fine, I expect. As regards the turbocharger and deposits, I would think that this sort of thing should not be an issue given that the oil was designed to be used hard in turbo-diesels... And for a long time, to boot. Not being difficult, just wondering is all. I would have said Go For It.

John.

 

[G-MAN]

Quote:

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As regards the turbocharger and deposits, I would think that this sort of thing should not be an issue given that the oil was designed to be used hard in turbo-diesels.

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I agree. This oil was designed to run in turbocharged diesel engines and I'm quite sure such turbos run just as hot as the ones in gas engines.

I think this oil would be fine in your Audi as long as you keep the OCIs reasonable.

 

[TooSlick]

The exhaust gas temps (EGT's) in turbodiesels run significantly lower than for turbocharged gas engines. In addition, turbodiesels (both pickups and OTR trucks) have much larger sump capacities. So the oil doesn't take nearly the beating it does in a 1.8L, 225 Hp gas engine turbo with a 4.8 qt sump capacity. Finally, the exhaust products from gasoline combustion tend to degrade the engine oil more than does #2 diesel fuel, which actually has decent lubricating properties. Hence you generally see very low levels of oxidation/nitration in diesel oil analyses and significantly higher flash points.

What's good for the Goose may not be good for the Gander...

TS

 

[Gary Allan]

I'd say that there has to be some merit to what you say TS. TDIs can get 25k+ out of an HDEO synth ..while gas (non-turbo) are pressed, in some instances, to make 15k. With diesels it appears more a matter of soot level then anything ..effectively ..filtration.

RTS, in my non-turbo gasoline experience, appears to be outstanding at deposit control ..even under "BITOG standard" extended OCIs (anything in excess of 5k-7.5k). 5+ years and nearly 60k show spotless internals from my limited view ..the last 3 years being with RTS.

I say ..use it and UOA it. Get a pump so you don't have to dump the sump to do it.

He didn't say how long he intends to run it ..nor how many miles he does a year ..nor much about his usage profile

 

[mcrn]

I agree with TooSlick. EGT's in diesels run cooler than gas engines. All he said is right, the bigger sump. blah blah blah. But It seems like if you wanted to try it doing a UOA like Gary said would be a good idea. I have thought about running it in my gas engine but its not a turbo.

 

[thunderchild]

I am grateful for all the ideas. I run this car about 10K a year. It is not my daily driver. I do a 5K OCI. I think I will try it and do a UOA to see how it works.

 

[G-MAN]

Quote:

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I am grateful for all the ideas. I run this car about 10K a year. It is not my daily driver. I do a 5K OCI. I think I will try it and do a UOA to see how it works.

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For 5K OCIs this oil would be fine, IMO.

 

[thunderchild]

That's what I was thinking also.

 

[bar1]

Isn't turbo deposits only a problem if you stop your engine immediately after a "spirited drive"? If you let everything cool down at low speed and low rpm a couple of minutes before you stop, turbo temperature shouldn't be a problem for (almost) any oil.

 

[Mike242GT]

FWIW, I have occasionally run RTS in Volvo red block turbos for 5K OCIs with no issues. GC is my oil of choice for these engines too, but I can't always find it. These are low pressure (7.5 psi) turbos and make just 162 hp out of 2.3L. Sump capacity is 4 qts. No, I haven't done a UOA, but the three engines in question still run strong at 230K, 160K and 150K.

 

[TooSlick]

If you're only going 10k a year, the chances are you'll get tired of the engine for other reasons before the turbo has to be replaced. Some of the comments I make fall under the heading of "best practices" and don't necessarily mean that what you're doing is going to result in rapid part failure....

TS

 

[thunderchild]

Being this is a diesel oil, I think that it would offer great cleaning qualities to this engine. Yes, I let it cool down after spirited driving before I turn it off. I am going to start driving it more. As of now it will sit for a week before I start it up. It is a fun car to drive.

 

[Drew99GT]

Rotella synthetic would be perfect in a turbo application. I ran Valvoline VR-1 10w-30 dino in a hard driven turbo application and never had a problem and saw with my own two eyes what the innards of the turbocharger looked like. They looked fine with no coking what so ever.

Running in vacuum for 3 to 5 minutes prior to shutting the engine off (ie no boost) will cool it down tremendously and prevent oil coking in the bearing cartridge. You don't even have to idle for minutes on end like many people say and turbo timers are an easy way to get your car stolen!